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Jaw morphology and fighting forces in stag beetles.
Jana Goyens1, Joris Dirckx2, Peter Aerts3
1University of Antwerp, Laboratory of Functional Morphology, Universiteitsplein 1, Antwerp 2610, Belgium University of Antwerp, Laboratory of Biophysics and BioMedical Physics, Groenenborgerlaan 171, Antwerp 2020, Belgium jana.goyens@uantwerpen.be.
The Journal of Experimental Biology
|July 21, 2016
Summary
Stag beetle jaw morphology varies greatly, with larger muscles enabling stronger bites. Despite differences in bite force, their jaw anatomy adapts to maintain similar stress levels, ensuring survival in fights.
Area of Science:
- Insect morphology
- Biomechanics
- Evolutionary adaptation
Background:
- Stag beetle male jaws are weapons in fights.
- Jaw morphology and bite force vary significantly across species.
Purpose of the Study:
- Investigate the relationship between stag beetle jaw morphology and bite force.
- Understand how jaw anatomy adapts to bite force in 16 species.
Main Methods:
- Comparative analysis of jaw morphology and muscle forces.
- Finite element simulations to calculate Von Mises stresses.
Main Results:
- Maximal muscle forces ranged from 1.8-33 N (18-fold difference).
- Larger bite muscles correlated with larger jaw volumes and elongated jaws.
- High muscle forces were linked to elevated bite forces (0.27-7.6 N, 28-fold difference).
- Similar Von Mises stresses (29-114 MPa) were observed across species despite varying bite forces.
Conclusions:
- Stag beetle jaw anatomy is adapted to bite force for effective combat.
- Elongated jaws increase fighting success, with mechanical disadvantage compensated by in-lever length.
- Species-specific adaptations ensure jaw structural integrity under different bite loads.
